Use a shadow knowledge base to understand any codebase. The .shadow/ directory mirrors the source tree with markdown files containing behavioral insights — known bugs, edge cases, implicit contracts, and user preferences. Always check the shadow before editing, debugging, or investigating code. When the user shares important context, write it to the shadow immediately. Invoke shadow-frog-init to create it, shadow-frog-update to refresh it, shadow-frog-dream for autonomous exploration, shadow-frog-meditate for shadow hygiene, or shadow-frog-viewer to browse it.
Installer avec Codex ou Claude Copiez ce prompt, collez-le dans Codex, Claude ou un autre assistant, puis laissez-le vérifier la page du skill et l'installer pour vous.
Une commande directe contourne le prompt de vérification. Examinez la source avant de l'exécuter.
Use a shadow knowledge base to understand any codebase. The .shadow/ directory mirrors the source tree with markdown files containing behavioral insights — known bugs, edge cases, implicit contracts, and user preferences. Always check the shadow before editing, debugging, or investigating code. When the user shares important context, write it to the shadow immediately. Invoke shadow-frog-init to create it, shadow-frog-update to refresh it, shadow-frog-dream for autonomous exploration, shadow-frog-meditate for shadow hygiene, or shadow-frog-viewer to browse it.
ShadowFrog
.shadow/ mirrors the source tree. Each source file has a .md shadow organized
by symbol. Each symbol section contains discoveries — behavioral insights anchored
to that code location.
Required Actions
Every time you work on code in a repo with .shadow/:
Read _prefs.md first — it contains project-wide conventions,
user preferences, and things the user explicitly wants to avoid.
Violating a preference wastes the user's time.
Read _cross/ discoveries — these are the highest-value findings,
spanning multiple files. List _cross/ and read any files whose titles
relate to the area you're working in. Cross-cutting discoveries reveal
hidden contracts, interaction bugs, and design patterns that per-file
shadows alone cannot capture.
Check _dreams/ for experiment results — _dreams/_index.md lists
autonomous exploration experiments. Read reports relevant to your task —
they contain verified bug analyses, attempted fixes, and architectural
insights. Dreams may contain knowledge not yet distilled into per-file
shadows, so always check when investigating a bug or unfamiliar area.
Before editing any file: read its shadow (.shadow/<path>.md),
check for cross-cutting discoveries about it, and apply
what you learn. The shadow contains known bugs, edge cases, and
implicit contracts discovered by previous sessions.
: discovery counts may be stale — always check
per-file shadows and directly rather than relying solely on
the index summary.
_cross/
Note
_index.md
_cross/
When the user explains something about code (gotcha, design intent,
warning, history): write a source: user discovery to the shadow
immediately. Do not ask where to put it — resolve the file::symbol
anchor yourself by searching _index.md, shadow files, and session
context (current file, recent edits).
When the user states a preference or convention (not tied to any
specific file): write it to _prefs.md immediately.
After code changes: run /shadow-frog-update
Directory Layout
.shadow/
.shadowignore Gitignore-syntax file for excluding paths from the shadow
_index.md File list with symbol counts and discovery counts
_prefs.md Project-wide user preferences (not tied to any file/symbol)
_cross/ Cross-cutting discoveries (span multiple files)
<slug>.md One file per cross-cutting discovery (descriptive kebab-case name)
_meta/
state.json Last commit, timestamps, counts
_dreams/ Dream experiment archive (detailed reports + diffs)
_index.md Table of all experiments with verdicts
<YYYYMMDD-HHMMSSZ-slug>/ One folder per experiment
report.md Structured report with YAML frontmatter
patch.diff Full implementation diff against base_commit
<mirrored tree>/ Per-file shadows
file.py.md Organized by symbol
Reference Notation
Canonical format: file_path::symbol_name
Examples: src/auth.py::authenticate_user, src/auth.py::UserAuth.validate,
src/auth.py (file-level, no symbol)
The symbol name is the stable anchor.
Per-File Shadow Format
# Shadow: src/auth.py**Language**: Python | **Lines**: 142 | **Last modified**: 2025-01-15
## File-Level- This module has no __all__ — all top-level names are public.
_(verified, source: exploration)_## `class UserAuth`### `UserAuth.validate`- Catches ALL exceptions and returns False — swallows
connection errors, making network failures look like invalid tokens.
_(verified, source: exploration)_## `authenticate_user`
- Silently returns None on expired tokens. Callers must check.
_(verified, source: exploration, labels: [bug])_
Also involves: `src/middleware.py::require_auth`## Cross-References- [db-connection-lifecycle](../_cross/db-connection-lifecycle.md)
(involves `src/db/connection.py::ConnectionPool`, `src/api/routes.py::get_user`)
Heading format (hard rule — parsers depend on this):
Top-level symbols (classes, functions, constants): ## heading with symbol in backticks
Nested symbols (methods): ### heading with symbol in backticks
## Cross-References — always last section
The viewer parser only matches the backtick form. A heading written as
### UserAuth.validate (no backticks) will have its discoveries
silently dropped from search/top output. Always wrap the symbol in
backticks, including for nested symbols.
# Database connection lifecycle**Category**: pattern
**Refs**:
-`src/db/connection.py::ConnectionPool.get`-`src/auth.py::authenticate_user`-`src/api/routes.py::get_user`**Discovery**: All database access goes through a connection pool that
silently reconnects on failure. First request after DB restart is slow (~2s).
_(verified, source: exploration)_
Preferences File (_prefs.md)
Project-wide user preferences and conventions that are not tied to any
specific file or symbol. These guide all agent work across the codebase.
# Preferences- No backward compatibility — only keep the latest code, no shims or aliases.
_(source: user)_- Use snake_case for all Python function and variable names.
_(source: user)_
- Prefer small, focused PRs over large sweeping changes.
_(source: interaction)_
Format:
- <preference or convention>
_(source: <user|interaction>)_
Preferences are always trusted (same rank as source: user). They don't
need verified/uncertain/refuted — if the user said it, it's a directive.
When to write to _prefs.md vs per-file shadow vs _cross/:
Applies to the whole repo, no specific file → _prefs.md
Applies to a specific file or symbol → per-file shadow
Applies to 3+ specific files → _cross/<slug>.md
Discovery Format
Per-file discoveries (no IDs — anchored by their file::symbol heading):
- <behavioral statement>
_(<verified|uncertain|refuted>, source: <exploration|user|interaction>)_
Also involves: `file::symbol`, `file::symbol`
With labels (optional — only when the discovery is actionable):
Slug naming: use descriptive kebab-case derived from the title.
Example: title "Database connection lifecycle" → filename db-connection-lifecycle.md
Labels
Labels mark actionable discoveries so agents can quickly scan for specific
types. Most discoveries are just knowledge — labels are only for findings
that call for action.
Label
Use when
bug
A defect that should be fixed
performance
A bottleneck or inefficiency
security
A vulnerability or unsafe pattern
feature-gap
Missing functionality or improvement opportunity
tech-debt
Code smell, duplication, refactoring opportunity
A discovery can have multiple labels: labels: [bug, security].
Omit labels entirely for pure observational knowledge.
Labels go in the metadata line:
_(verified, source: exploration, labels: [bug])_
Cross-cutting discoveries can also have labels — add them to the metadata line.
Fields
verified|uncertain|refuted — verification status
source: exploration — agent discovered via code analysis
source: user — human stated it in conversation
source: interaction — emerged from collaborative work (debugging, refactoring)
labels: [...] — optional, actionable labels (see table above)
Also involves: — file::symbol refs to other code locations (required if discovery touches other files)
Dream report: — optional, _dreams/<dream-id>/ link for experiment-derived discoveries
Symbol anchoring: every source symbol has a ##/### heading in its shadow
Also involves: per-file discoveries list other file::symbol locations
Cross-ref back-pointers: per-file ## Cross-References links to _cross/<slug>.md entries
Cross-cutting refs: _cross/<slug>.md**Refs**: lists all involved file::symbol locations
Links 4 and 5 are bidirectional: if _cross/db-connection-lifecycle.md references
src/auth.py::fn, then src/auth.py.md must list it in ## Cross-References, and vice versa.
Seven Invariants
Every included source file has exactly one shadow at .shadow/<path>.md
Every symbol in source has a ##/### heading in its shadow
Per-file discoveries touching other files have Also involves: with file::symbol
Every entry in ## Cross-References has a corresponding _cross/<slug>.md file
Cross-cutting filenames are unique (enforced by filesystem)
No duplicate discoveries (same behavioral claim at same symbol)
To audit a shadow for structural drift (invariant 3 format, invariants 4–5,
plus enum and heading-format guards), locate the viewer script and run it:
VIEWER=""for DIR in .github/skills/shadow-frog-viewer .claude/skills/shadow-frog-viewer; do
[ -f "$DIR/shadow-viewer.py" ] && VIEWER="$DIR/shadow-viewer.py" && breakdone
python3 "$VIEWER" --check-invariants
Exits 0 if clean, 1 with one violation per line otherwise. Invariant 3 is
checked for anchor format only (not existence of the referenced file or
symbol); invariants 1, 2, and 7 require source parsing / semantic match and
are not statically checked; invariant 6 is filesystem-enforced.
Lookup Commands
# File's shadowcat .shadow/src/auth.py.md
# Specific symbol's knowledge
grep -A 20 "## \`authenticate_user\`" .shadow/src/auth.py.md
# Cross-cutting discoveries for a file
grep -rl "src/auth.py::" .shadow/_cross/
# Search by topic
grep -rl "error.handling\|exception" .shadow/ --include="*.md"# All user-shared knowledge
grep -r "source: user" .shadow/ --include="*.md"# Project-wide preferencescat .shadow/_prefs.md
# List all cross-cutting discovery filesls .shadow/_cross/
Write a short verification script (test, assertion, or probe) that would
confirm or refute the claim
Run it
Based on the result → verified or refuted
Prefer do-based for claims about runtime behavior, performance, error handling
paths, or race conditions. Prefer observe-based for claims about code structure,
types, or static properties.
Dedup and Writing Rules
Before writing any discovery, follow this procedure:
Read before write: Read all existing discoveries under the target
file::symbol. If an existing discovery makes the same behavioral
claim (even if worded differently) → update the existing one. If the
new one extends an existing one → merge into a single richer entry.
If they conflict → investigate the code, keep the correct one, mark
the other refuted.
Append, don't replace: If the symbol already has discoveries,
append your new one after them. If there is a _No discoveries yet._
placeholder, remove it and write your discovery. Never use the
placeholder as an edit anchor if it's already gone — read the file first.
Write in canonical format (see Discovery Format above)
Fix bad format: if you see any existing content that doesn't
follow the canonical format, fix it in place
For cross-cutting, search _cross/ for overlapping **Refs**: sets
before creating a new entry. Only create _cross/<slug>.md for
discoveries spanning 3+ files — otherwise use per-file entries with
Also involves: references.
Related Skills
/shadow-frog-init — create .shadow/ for a new repo
/shadow-frog-update — refresh shadows after changes or from conversation
/shadow-frog-dream — autonomous exploration and experimentation while user is AFK
/shadow-frog-meditate — deduplicate, merge, and resolve conflicting discoveries
/shadow-frog-viewer — browse and query the shadow (overview, search, preferences, recent)
